[env-trinity] Fish farms linked to sea lice outbreak

[Josh Allen]

Fish farms linked to sea lice outbreak


Parasite found on farmed B.C. salmon infecting wild fish stocks,
scientists say


http://www.theglobeandmail.com/servlet/story/LAC.20070227.BCLICE27/Email
TPStory/National 


CATHRYN ATKINSON 

Special to The Globe and Mail

VANCOUVER -- For the first time in Canada, scientists have used data
from the world's largest aquaculture company to draw a link between sea
lice from Atlantic salmon on British Columbia fish farms and soaring
infection rates in wild salmon migrating nearby.

After an infestation caused the near collapse of wild spring salmon
stocks in the Broughton Archipelago in 2002, Craig Orr, executive
director of the Watershed Watch Salmon Society, collected information
from the Norwegian company Marine Harvest on sea lice at its fish farms
in the region. 

"We had predicted 3.6 million [wild] salmon returning to the Broughton
in 2002. What we got back, according to the [Department of] Fisheries
and Oceans count, was 147,000 fish - a 97-per-cent crash that was only
in the Broughton," said Dr. Orr, who is also the science co-ordinator
for the Coastal Alliance for Aquaculture Reform. 

Watershed Watch is a non-governmental organization that monitors B.C.
water systems.

Dr. Orr also studied a sea lice action plan brought in by the provincial
government after the collapse -- the only time any such plan to curb sea
lice population growth has occurred in B.C. -- in his search for growth
patterns in the parasite's demographics.

The results were published last week in an article for the North
American Journal of Fisheries Management.

Dr. Orr discovered that 12 active, open net-cage farms in the Broughton,
which is composed of dozens of islands between the B.C. mainland and the
northern tip of Vancouver Island, contained between one and five million
Atlantic salmon and produced billions of lice eggs over an 18-month
period in 2003 and 2004. Louse-egg production peaked during late winter
in both years, just before the seaward migration of juvenile wild
salmon.

His article confirms that when lice-egg production was reduced by early
harvesting of farmed salmon, infections on wild juvenile salmon near the
farms declined dramatically -- including a 42-fold reduction near one
emptied farm.

"What we do now know is what's happening on these farms. And it's
transparent, finally. And that's critical," Dr. Orr said. 

"We do hope that the [government] management agencies and the industry
are willing to work towards reducing those peaks of lice just before the
juvenile fish come out. That's why we're doing all this."

He praised Marine Harvest for making the data available, something
aquaculture companies have done in Europe but not yet in Canada. 

Dr. Orr said he wants to see a change in practices, especially from the
provincial government, which oversees fish farming in British Columbia.

"We are critical of government because they aren't producing data. They
aren't making these companies share the data like they are in Europe,
with the exception of Marine Harvest -- and they didn't make them.
[Marine Harvest] volunteered it," Dr. Orr said.

The migration of wild spring salmon usually begins in the first days of
March. 

 

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